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Single step preparation of $CeO_2/CeAlO_3/\gamma-Al_2O_3$ by solution combustion method: Phase evolution, thermal stability and surface modification

Prakash, AS and Shivakumara, C and Hegde, MS (2007) Single step preparation of $CeO_2/CeAlO_3/\gamma-Al_2O_3$ by solution combustion method: Phase evolution, thermal stability and surface modification. In: Materials Science and Engineering: B, 139 (1). pp. 55-61.

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Abstract

Phase evolution of $CeO_2/\gamma-Al_2O_3$ system synthesized from single step solution combustion method is examined here. The nominal compositions of ceria and alumina in $(CeO_2)x/(Al_2O_3)_{1-x}$ are varied from x = 0.0 to 0.66 to yield end compositions, $\gamma-Al_2O_3$ to stoichiometric $CeAlO_3$ phase. For the composition x = 0, the phase formed is $\gamma-Al_2O_3$,and for x = 0.2, $CeAlO_3$ is formed over $\gamma-Al_2O_3$. As the cerium content increased beyond x = 0.2, $CeO_2/CeAlO_3/\gamma-Al_2O_3$ oxides are formed. Heating $CeAlO_3/\gamma -Al_2O_3$ in air above $700 ^oC$ resulted in transformation to $CeO_2/\gamma -Al_2O_3$ and the subsequent reduction in $H_2$ gave back $CeAlO_3/\gamma -Al_2O_3$.TEM studies showed $CeAlO_3$ crystallites growth on $\gamma -Al_2O_3$ and the oxidized sample showed $CeO_2$ formation over $CeAlO_3$ , which in turn interfaced with $\gamma -Al_2O_3$ phase. XPS a analysis of $CeAlO_3/\gamma -Al_2O_3$ phase showed the presence of Ce in +3 and +4 state indicating surface oxidized $CeAlO_3$ phase. Epitaxial relation for growth of $CeAlO_3$ over $\gamma - Al_2O_3$ and $CeO_2$ over $CeAlO_3$ is demonstrated in the study, where adhesion of $CeO_2$ over $\gamma -Al_2O_3$ is via $CeAlO_3$ phase at the Interface.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to Elsevier.
Keywords: Solution combustion synthesis;CeAlO3;Cerium oxides;Solid–solid interfaces
Department/Centre: Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited: 27 Aug 2007
Last Modified: 19 Sep 2010 04:39
URI: http://eprints.iisc.ernet.in/id/eprint/11780

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